Azo dye.



UNITED STATES Patented May 12, 1963.

PATE T OFFICE.

' MYRTIL KAHN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

AZO DYE.

SPECIFICATION forming part of Letters Patent No. 727,963, dated May 12, 1903.

Application filed February 16, 1903.

mula:

so,rr x

(X meaning a hydrogen atom which can be replaced by halogen atoms, SO,H or --CH,,) such as ortho-amidophenol or cresol sulfonic acids, ortho amidophenol chloro sulfonic acids, ortho amidophenol orthopara disulfonic acid, or the like, with 1:7 amidonaphthol having the formula:

ir s, wa i I I The new dyestuffs thus obtained are brownish-black powders soluble in water with from a reddish-violet to bluish-violet color, turning blue by adding a solution of sodium carbonate, dyeing Wool from acid-baths violet shades, turning black by a subsequent treatment with chromium compounds, reacting as oxidizing agents. The black shades thus obtained are distinguished by great fastness to the potting process, whichis a finishing process for woolen piece goods. In this process the goods are entered into boiling water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and, according to the effect desired,the potting may be repeated several times.

In carrying out my process practically I fierial No. 143,630. (No specimens.)

can proceed as follows, the parts being by weight: Nineteen parts of ortho-amidophenol= para-sulfonic acid SOIBH are diazotized in the usual manner, and the resulting diazo compound is stirred into a solution of sixteen parts of 1:7-amidonaphtholin caustic-soda lye and mixed with ice-water. Care must be taken that the mixture remains alkaline during the whole reaction. After being stirred for some time the excess of caustic-soda lye is neutralized by means of hydrochloric acid, and the new dyestufi is precipitated by the addition of common salt, filtered OE, and dried.

The new coloring-matter thus obtained is in the shape of the sodium salt a brownishblack powder soluble in water and in alcohol with a violet color and soluble in concentrated sulfuric acid of 66 Baum with a bluish-red color, a reddish-brown precipitate being obtained by the addition of ice. It dyes wool from acid-bath violet shades. By subsequently treating the dyed fiber with chromium compounds, reacting as oxidizing agents-such as chromates, bichromates, or the like-the shades are changed to black distinguished for great fastness to the potting process. They also resist milling and washing and possess a good fastness against the action of light.

Having now described my invention, what I claim is- 1. The herein-described new azo d yestuifs derived from ortho-amidophenol derivatives having the above-given general formula and 1 :7-an1idonaphthol which,when in a dry state, are brownish-black powders soluble in water with from a reddish-violet to bluish-violet color turning blue by adding a solution of sodium carbonate; dyeing woolfrom acid-bath violet shades turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as here- 1 let shades which are changed to black by a inbefore described. subsequent treatment with chromium corn- 2. The herein-described new azo dyestufi? pounds reacting as oxidizing agents, substan- 15 derived from ortho-ainidophenol para-sultially as hereinbefore described.

5 fonic acid and 1:7-amidonaphthol which, in In testimony whereof I have signed my the shape of the sodium salt, is, when dry and name in the presence of two subscribing witpulverized, a brownish-black powder soluble nesses. in Water and in alcohol with a Violet color T 1 v and being soluble in concentrated sulfuric M1 RrlIL KAIIN' IO acid of 66 Baum with a bluish-red color, a Witnesses:

reddish-brown precipitate being obtained by OTTO KNIG, adding ice; dyeing wool from acid-bath vio- J. A. RITTERSHAUS. 

